view libtommath/bn_mp_fwrite.c @ 1861:2b3a8026a6ce

Add re-exec for server This allows ASLR to re-randomize the address space for every connection, preventing some vulnerabilities from being exploitable by repeated probing. Overhead (memory and time) is yet to be confirmed. At present this is only enabled on Linux. Other BSD platforms with fexecve() would probably also work though have not been tested.
author Matt Johnston <matt@ucc.asn.au>
date Sun, 30 Jan 2022 10:14:56 +0800
parents 1051e4eea25a
children
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#include "tommath_private.h"
#ifdef BN_MP_FWRITE_C
/* LibTomMath, multiple-precision integer library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */

#ifndef MP_NO_FILE
mp_err mp_fwrite(const mp_int *a, int radix, FILE *stream)
{
   char *buf;
   mp_err err;
   int len;
   size_t written;

   /* TODO: this function is not in this PR */
   if (MP_HAS(MP_RADIX_SIZE_OVERESTIMATE)) {
      /* if ((err = mp_radix_size_overestimate(&t, base, &len)) != MP_OKAY)      goto LBL_ERR; */
   } else {
      if ((err = mp_radix_size(a, radix, &len)) != MP_OKAY) {
         return err;
      }
   }

   buf = (char *) MP_MALLOC((size_t)len);
   if (buf == NULL) {
      return MP_MEM;
   }

   if ((err = mp_to_radix(a, buf, (size_t)len, &written, radix)) != MP_OKAY) {
      goto LBL_ERR;
   }

   if (fwrite(buf, written, 1uL, stream) != 1uL) {
      err = MP_ERR;
      goto LBL_ERR;
   }
   err = MP_OKAY;


LBL_ERR:
   MP_FREE_BUFFER(buf, (size_t)len);
   return err;
}
#endif

#endif